The purpose of this contract is to provide logistical and data support for a study designed to determine whether or not children who ingested chloride-deficient formula as infants suffered long- term effects associated with or caused by this exposure. The study will involve primarily the examination of two groups of exposed children and their appropriate controls. Part A of the study will include a mailed survey of the parents of children born between October 1, 1977 and July 1, 1979 and enrolled in one of three school districts located near the Washington, D.C. area. The results of this survey will be used to assemble two groups of children: one exposed to one of the two chloridedeficient formulas and the other exposed to other soy formulas. This latter group will be matched by age, race, sex and socioeconomic status to the exposed group. These two groups will require: (a) A short telephone interview of a parent of each child to confirm exposure status and obtain additional demographic and medical information. (b) The acquisition and abstraction of the medical records of these study children. (C) The examination of these children in the schools using three well-known, standardized developmental test. (WISC-R, Boston Naming and Rey-Osterreith). Part B of the study will involve a second group of children from variety of locations in the United States who will be evaluated at the NIH together with a sibling (if one is within two years of age of the index child). These index children will be selected from a group of children who had hypochlorcmic metabolic alkalosis while using one of the two Syntex formulas. These children and their siblings will be given the same battery of tests as the children selected from the school population. In addition to the school battery, they will have a physical and neurological examination as well as visual screening and two additional developmental tests (Beery Visual-motor integration test and Tell-A-Story). Controls for this group of children will be selected from the population- based group. This sub-group of the population based sample (including both exposed and unexposed children) will also be given the physical and neurological examination, and the additional specialized developmental testing. In addition to this full battery, the children with hypochloremic metabolic alkalosis, their sibs, and the controls selected from the school population-based cohorts will require: (i) An extensive parental interview (ii) The acquisition and abstraction of medical records outlined above.